FASTSim: A Model to Estimate Vehicle Efficiency, Cost and Performance

Aaron Brooker, Jeffrey Gonder, Lijuan Wang, Eric Wood, Sean Lopp, Laurie Ramroth

Research output: Contribution to conferencePaperpeer-review

104 Scopus Citations


The Future Automotive Systems Technology Simulator (FASTSim) is a high-level advanced vehicle powertrain systems analysis tool supported by the U.S. Department of Energy's Vehicle Technologies Office. FASTSim provides a quick and simple approach to compare powertrains and estimate the impact of technology improvements on light- and heavy-duty vehicle efficiency, performance, cost, and battery life. The input data for most light-duty vehicles can be automatically imported. Those inputs can be modified to represent variations of the vehicle or powertrain. The vehicle and its components are then simulated through speed-versus-time drive cycles. At each time step, FASTSim accounts for drag, acceleration, ascent, rolling resistance, each powertrain component's efficiency and power limits, and regenerative braking. Conventional vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, all-electric vehicles, compressed natural gas vehicles, and fuel cell vehicles are included. Powertrains with electric-traction drive can optionally be simulated using electric roadway technologies such as dynamic wireless power transfer. FASTSim also has an interface for running large batches of real-world drive cycles. FASTSim's calculation framework and balance among detail, accuracy, and speed enable it to simulate thousands of driven miles in minutes. The key components and vehicle outputs have been validated by comparing the model outputs to test data for many different vehicles to provide confidence in the results. A graphical user interface makes FASTSim easy and efficient to use. FASTSim is freely available for download from the National Renewable Energy Laboratory's website (see

Original languageAmerican English
Number of pages12
StatePublished - 14 Apr 2015
EventSAE 2015 World Congress and Exhibition - Detroit, United States
Duration: 21 Apr 201523 Apr 2015


ConferenceSAE 2015 World Congress and Exhibition
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
Copyright © 2015 SAE International.

NREL Publication Number

  • NREL/CP-5400-63623


  • analysis tools
  • FASTSim
  • Future Automotive Systems Technology Simulator
  • powertrain analysis
  • technology improvements


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